Advice on upgrading PC

[PyloTheGreat]

I have a default, untouched Acer Aspire M5800, with intel quad 2 quad CPU Q9400 @ 2.66GHz(4 CPUs), ~2.7 GHz and 4096 MB of RAM. My graphics card is the NVIDA GeForce GT 230. I'm not sure where this rig ranks and was wondering where it could use some upgrading. I mostly use it for gaming, ARMA 2 ect. and was wondering what improvements my rig needs. I'm a complete dunce at this and the difficulty of installation matters to me as I'm quite uncomfortable about taking my PC apart. Which areas of my PC could I improve on? It would be great if you could suggest more 'mainstream' devices that are common in Asia, more specifically, Singapore. Thanks in advance.

 

[brinks]

You should upgrade your video card and add a rear case exhaust fan if you don't have one. Not sure what parts are available in Singapore.